Warp size lubricants can be used to improve weaving performance without detriment to subsequent processing. Sizing lubricants are purported to improve properties of the sizing film produced. They are believed to help produce a smoother size film, a slicker film, enhance the flexibility or folding endurance of the film, and facilitate greater film elongation. At the same time, they are believed to have no detrimental effect on the adhesion of the sizing agent to the warp yarn. Sizing lubricants are also alleged to improve weaving performance by reducing yarn breaks by reducing the coefficient of friction between adjacent yarns and between yarns and machinery parts, while also improving the abrasion resistance of the sized yarn. Likewise, sizing lubricants are believed to reduce wear on machinery parts. Subsequent processes such as preparation (desizing, scouring, bleaching), dyeing, printing, and finishing should be either unaffected by the sizing lubricant or effected in a positive manner.
Presently, virtually all textile warp size lubricants are made from mixtures of tallow, vegetable and mineral oil, and/or paraffin wax. These materials are available in solid (powder, granules, beads, flakes) or liquid form. Flake form is most common. These traditional lubricants, or perhaps better described as softeners, are insoluble or dispersible in water.
The actual effects of traditional lubricants are in many cases opposite to the theoretical effects. Traditional lubricants may also produce other unexpected negative effects.
For examples, traditional warp size lubricants may not improve size film characteristics as expected. In contrast, these lubricants may soften the size film, make the size film grainy rather than smooth or slick, and significantly weaken the size film. Furthermore, traditional size lubricants may hinder film formation. These lubricants can also create unexpected effects. These effects include a significant reduction in foaming of the sizing agent in the preparation vessel, storage vessel, and size box as well as a minimization of sticking of the size to the drying cylinders (even when the dry cylinders have scratches on the Teflon coating). However, these effects can be accomplished more effectively by the use of other chemicals. Specially formulated anti-foams and defoamers are more cost and performance effective than traditional lubricants. Likewise, formulated anti-sticking additives are better performers compared to traditional lubricants when such a property is needed.
In many instances, the effects of traditional sizing lubricants in weaving are contrary to the theoretical effects. Most of the products used as traditional lubricants may not reduce the coefficient of friction between adjacent yarns or between yarns and machinery parts. Most commonly, the opposite is true. An increase in the coefficient of friction is normally observed. There is no improvement in abrasion resistance. In nearly every instance, there is a significant decrease in abrasion resistance. Of greatest significance, there is no reduction in yarn breaks when using traditional lubricants that is attributable to the sizing lubricant. Statistics show there to be an increase in the number of yarn breaks.
The traditional lubricants in preparation and subsequent processing are not easy to make water-soluble. These lubricants require high water temperatures, larger quantities of water, and the use of chemicals for thorough preparation (desize, scour, bleach). Furthermore, these lubricants have a well-documented history of creating dyeing, printing, and finishing faults. These faults include streaks, dye resist spots, and poor absorbency.
Thus, there is a need to develop a new type of sizing lubricant that overcomes the disadvantages of traditional sizing lubricants and can provide better performance.